| NSF Org: |
AGS Division of Atmospheric and Geospace Sciences |
| Recipient: |
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| Initial Amendment Date: | April 7, 2015 |
| Latest Amendment Date: | May 2, 2017 |
| Award Number: | 1503155 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Nicholas Anderson
nanderso@nsf.gov (703)292-4715 AGS Division of Atmospheric and Geospace Sciences GEO Directorate for Geosciences |
| Start Date: | May 1, 2015 |
| End Date: | April 30, 2019 (Estimated) |
| Total Intended Award Amount: | $556,155.00 |
| Total Awarded Amount to Date: | $660,546.00 |
| Funds Obligated to Date: |
FY 2016 = $320,023.00 FY 2017 = $133,934.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
4333 BROOKLYN AVE NE SEATTLE WA US 98195-1016 (206)543-4043 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
4333 Brooklyn Ave NE Seattle WA US 98105-1016 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Physical & Dynamic Meteorology |
| Primary Program Source: |
01001617DB NSF RESEARCH & RELATED ACTIVIT 01001718DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
The three major types of precipitating cloud systems in the atmosphere are deep convection, frontal systems, and tropical cyclones. This project examines how each is affected by the presence of mountains. The research will analyze existing datasets including those of several past National Science Foundation funded field campaigns.
Intellectual Merit:
Heavy precipitation and flooding in regions of complex terrain can be understood and anticipated by identifying key ingredients. This research identifies such ingredients associated with each of the three principal storm types. The ingredients for deep convection will be examined and identified by comparing behavior of heavy rain-producing convection over the Himalayas, Andes, Central Mountains of Taiwan, and the Sierra Madre Occidental of Mexico. These different venues provide a variety of synoptic and orographic settings so that the important ingredients for intense rainfall and flooding will be identified through comparison of the storms in these different regions. The parental synoptic conditions range from baroclinic waves dipping equatorward over Asia, to monsoonal conditions, to equatorial waves, and diurnal forcings. The ingredients for enhancement of precipitation when fronts cross mountain ranges will be examined for the coastal mountains of British Columbia to test the hypothesis that shear and thermally-induced turbulence enhance windward side precipitation. The ingredients associated with the passage of tropical cyclones over mountains will be studied by examining Hurricane Karl (2005) and Tropical Storm Dolly (2014) as they entered and crossed the Sierra Madre Oriental of Mexico. The roles of terrain-locked gravity waves and triggering of convection over the mountains will be examined as ingredients for modifying and prolonging the precipitation in the eyewalls and rainbands of tropical cyclones. Through studying these types of enhancement of precipitation by the major atmospheric precipitation systems as they pass over mountains and identifying key ingredients, this project will contribute to a more general understanding of the effects of mountains on precipitating clouds.
Broader Impacts:
This work will have the broader impact of laying groundwork for improved forecasting of heavy precipitation in regions of the earth most prone to flooding and disastrous societal impacts. Further, by better understanding how mountains affect storms, future studies may better anticipate how the patterns of occurrence of natural disasters might be altered in a changing climate. In addition, this project will optimize the use of past field campaign datasets and will contribute to training women and minorities for atmospheric sciences research.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
This project investigated precipitation processes Asia, South America, and North America. The emphasis was on how mountains affect the precipitation processes in large-scale storms such as hurricanes and fronts. Hurricanes are most deadly when the pass over mountainous terrain, and in this study we showed how the relative orientation of the winds to the mountains of coastal Mexico affected the clouds and precipitation in the landfalling Hurricane Karl (2010). We have shown how convection is released and becomes organized on the mesoscale in the lee of the Andes when waves in the westerlies pass over that mountain range. We further showed how a wave in the westerlies can lead to extreme upslope flow and flooding in the Himalayan region. Most of the study, however, was focused on the western U.S. We showed how small-scale convective structures in the form of so-called Kelvin-Helmholtz wave form in the flow over the windward side of the Sierra Nevada Range when fronts pass over California. The last part of the project was concerned with a field campaign over the Olympic Mountains. In this project, called OLYMPEX, five research radars and two aircraft were deployed to investigate wintertime frontal systems passing over the Olympic Range. It was found that great enhancement of the precipitation forming processes occurred both at low levels in the form of small raindrops and aloft where the formation of snow was increased as the flow rose over the terrain. The special observations that we made allowed these processes to be measured and quantified, and the observations shed further light on the formation of Kelvin-Helmholtz waves in the flow rising over the topography. Notably OLYMPEX provided the most detailed observations yet obtained in so-called ?atmospheric river? storms that produce flooding on the west coast.
Last Modified: 07/29/2019
Modified by: Robert A Houze
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